Diving octopuses, or alternate air sources, are critical safety devices designed to provide emergency air to a buddy in distress. They serve as a secondary regulator, ensuring divers have a reliable backup in unforeseen circumstances. Products were evaluated based on breathing performance, material durability, ease of use, and feature analysis, alongside consideration of user reviews.
ScubaPro S270 Octopus
$329.00
Its air-balanced valve and lightweight yet durable construction offer smooth breathing across varying conditions and depths.
Search on AmazonCressi Octopus XS, light and flexible octopus for scuba diving, made in Italy, Yellow / Black
$124.95
This model provides excellent value with proven downstream performance and low maintenance, ideal for divers seeking affordability.
Search on AmazonSCUBAPRO R105 Octopus
$229.00
Featuring a rugged metal valve housing and a classic downstream design, it prioritizes long-term reliability and robust performance.
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- COMPACT & LIGHTWEIGHT - The MARES SXS Octopus is the smallest, most compact second stage, ideal for travel divers; Made from ultralight technopolymer, it's durable yet light, making it easy to carry and handle underwater
- VORTEX ASSISTED DESIGN - Equipped with MARES' Vortex Assisted Design (VAD), the 2nd stage SXS Octopus features a "curved" bypass tube that optimizes airflow for a smooth and natural breathing experience
- BETTER VISIBILITY - A standout feature of the SXS Octopus is its lateral exhaust tube, which improves visibility; The exhaust positioning ensures bubbles are directed away from your face, offering unobstructed views throughout your dive
- LEFT OR RIGHT-SIDED USE - The SXS offers maximum versatility with its ability to be used on either the left or right side; This design allows divers to customize their setup based on personal preference or dive conditions
- SUPERFLEX HOSE & SOFT PURGE BUTTON - The SXS Octopus features a flexible Superflex hose that ensures freedom of movement while diving; The soft purge button is designed for quick clearing of the second stage, perfect for cold water or emergency
- Atomic B2 Second Stage Octopus
- Each Atomic octo is designed and precision-built to perform as perfectly as its primary counterpart
- All Atomic Octopus models come with a standard extra-long 36” hose
- The Comfort Swivel is the perfect design aspect for a safe second
- House of Scuba is an Authorized Atomic Dealer
- The Cressi Octopus MG is a pneumatically balanced valve designed with a Venturi effect adjustment switch, Cressi's patented elliptical membrane diaphragm and patented low-friction lever.
- The Octopus regulator air delivery system without injector has an internal heat exchange, cam-lock system to open the case and a body in noise-absorbent techno Polymer.
- Removable techno Polymer deflector and removable mechanical parts.
- The hose is an extremely light and flexible weighing only 5.4 oz. (153 g) with the regulator coming in at 6.42 oz. (182 g). Regulator is certified to CE standard Annex B EN 250:2014 for cold water.
- The hose and purge cover are in bright yellow color for easy identification in an out-of-air-emergency.
- The MG Balanced is designed and made in Italy by Cressi, an Italian brand pioneer in scuba diving, snorkeling and swimming equipment since 1946.
- Complete Treasure Set: This pirate treasure chest set includes 66 items, featuring 10 large diving gems, 25 small diamonds, coins, a yellow octopus, a green turtle, and 8 different starfish. Perfect for imaginative underwater play with no small choking...
- Colorful Gem Decor: Includes vibrant diving gems in blue, green, red, yellow, and pink, making underwater hunt fun and visually
- Easy to Carry & Store: Sturdy wooden treasure chest measures 5.7 x 4 x 4 inches, perfect for pool dive play. Lightweight and easy to store all gems, coins, and sea creatures
- Fun for: Suitable for pool dive play with diving gem pieces and underwater set components. Encourages active play, hand-eye coordination, and problem-solving skills.
- Perfect Gift & Party Set: Ideal for summer pool parties, beach days, or outdoor play. Makes a great gift as a pirate treasure chest set, turning ordinary pool time into an exciting treasure hunt.
- Secure the strap to D rings by passing the square end through the slot end of the strap.
- Easy to adjust, bright color designs, easy to quickly identify underwater.
- Easy installation, suitable for most mouthpieces.
- Make from Silicone materials, keep soft even in cold water.
- The square end is designs to hold the mouthpieces fastened to the Octopuses.
- Mechanically balanced for smooth and easy inhalation and exhalation.
- Under-chin exhaust system, directing bubbles to the sides.
- The spring clip not only can rotate 360 degree, but also easily clamps, and can operated at any directions
- It can secure the diving equipment stable and effectively, the respirator from moving or being lost, and easy to carry Octopuses regulator with you, ensuring that your diving activity are safe
- Suitable for fixing regulators, diving watches and low or highly pressure hoses, perfect for Scubas diving, snorkeling, freediving, and underwater photography
- Clip is make of hard, strong and wear resistance Dives Webbings is make of nylons, light weight and Enduring Octopuses holder rings is make of Silicones, soft, elastics, not easy to deforms
- The unique diving Flags pattern is eye catching and look very designs Suitable for Scubas Diver and snorkelers
- Can attach to the diving equipment, to your second stage hose effectively
- With strong and enduring clip, quickly clip designs makes it easy to place
- Great accessories for Scubas diving, snorkeling
- The is strong enough to keep Octopuses/Regulator in place of the water
- Designs to secure Octopuses attachments or other similar hoses conveniently
- The square end is designs to hold the mouthpieces fastened to the Octopuses
- Easy installation, suitable for most mouthpieces
- Make from Silicone materials, keep soft even in cold water
- Secure the strap to D rings by passing the square end through the slot end of the strap
- Easy to adjust, bright color designs, easy to quickly identify underwater
This article is part of our complete guide Water Sports — browse all our comparisons and buying guides.
Last update on 2026-07-17 / Affiliate links / Images from Amazon Product Advertising API
How to Choose the Best Diving Octopuses
Valve Design and Breathing Performance
The core of an octopus's performance lies in its valve design, which dictates the ease of breathing under stress. Downstream valves, like those found in the Cressi Octopus XS and SCUBAPRO R105 Octopus, are known for their simplicity and dependability. They are a time-tested design that typically offers consistent air delivery. However, air-balanced valves, as seen in the ScubaPro S270 Octopus, are engineered to smooth out inhalation effort regardless of depth or tank pressure, providing a potentially more comfortable and less strenuous breathing experience during an emergency. The Mares Rover Scuba Diving Compact 2nd Stage Octopus Regulator goes further with its Vortex Assisted Design (VAD), which is intended to create a swirling flow of air to reduce breathing resistance.
Material Durability and Weight
The construction materials significantly impact an octopus's lifespan and its feel in the water. Metal valve housings, such as the one on the SCUBAPRO R105 Octopus, are known for their ruggedness and increased overall reliability, often preferred for their ability to withstand harsh conditions and impacts. In contrast, many modern octopuses, including the Cressi Octopus XS and Mares Rover, utilize technopolymers or fiberglass-reinforced nylon for their casings. These materials, like the fiberglass-reinforced nylon core with a PU outer layer on the ScubaPro S270 Octopus, offer the advantage of being lightweight and durable, reducing jaw fatigue and overall bulk without necessarily compromising strength.
Ergonomics and Air Sharing Accessibility
An effective octopus must be easily deployable and comfortable for both the donor and the recipient. Features like the reversible hose attachment on the SCUBAPRO R105 Octopus offer versatility in configuration, making it adaptable to various tank setups, including pony or deco tanks. The purge button's design is also crucial; the Mares Rover features a large purge button with a 'dynamic hinge' design, aiming for easy operation even with thick gloves. Furthermore, the Aqua Lung ABS Octopus highlights an innovative low-profile design and a unique 120-degree angle between the hose and mouthpiece, which is specifically optimized for comfortable and efficient air sharing with a buddy, minimizing drag and facilitating a natural head position.
Pros & Cons
SCUBAPRO R105 Octopus
Pros
- Features a rugged metal valve housing for enhanced durability and reliability.
- Classic downstream valve design ensures dependable breathing performance.
- Reversible hose attachment provides flexibility for various tank configurations.
Cons
- Metal construction may result in a heavier unit compared to technopolymer alternatives.
- Classic design might not incorporate the latest advancements in breathing ease.
Cressi Octopus XS, light and flexible octopus for scuba diving, made in Italy, Yellow / Black
Pros
- Highly affordable, offering maximum value for a secondary regulator.
- Proven downstream system provides reliable air delivery.
- Low maintenance requirements simplify ownership.
Cons
- Traditional dimensions may be less compact than some modern designs.
- Technopolymer body, while durable, may not offer the same perceived ruggedness as metal housings.
Mares Rover Scuba Diving Compact 2nd Stage Octopus Regulator
Pros
- Designed for heavy-duty, intensive use with ultralight technopolymers.
- Equipped with MARES' Vortex Assisted Design (VAD) for effortless breathing.
- Large purge button with a 'dynamic hinge' allows for easy operation.
Cons
- Ultralight technopolymers, while durable, may feel less substantial than metal construction.
- The specific VAD technology might necessitate brand-specific servicing or parts.
Common Mistakes to Avoid
Overlooking Valve Technology for Breathing Ease
One common mistake divers make is assuming all octopuses deliver air with the same ease. While a classic downstream valve, like that in the SCUBAPRO R105 Octopus or Cressi Octopus XS, is dependable, it may require more inhalation effort than an air-balanced valve. For instance, the ScubaPro S270 Octopus features an air-balanced valve specifically designed to smooth out inhalation effort across varying depths and supply pressures. Neglecting this distinction can lead to a less comfortable or more effortful breathing experience for a buddy during a high-stress emergency.
Ignoring Material Construction and Long-Term Durability
Divers sometimes overlook the materials used in an octopus's construction, focusing solely on initial cost. Products like the SCUBAPRO R105 Octopus boast a rugged metal valve housing, which in practice, tends to offer superior resistance to impact and wear over time. In contrast, while ultralight technopolymers used in the Mares Rover or the fiberglass-reinforced nylon of the ScubaPro S270 Octopus are durable and lightweight, users report that metal construction often provides an added sense of robustness for intense use or frequent travel, impacting the octopus's lifespan and reliability in demanding conditions.
Failing to Consider Hose Routing and Buddy Breathing Ergonomics
The physical configuration of an octopus is crucial for effective air sharing. A mistake is choosing an octopus without considering how it will be deployed and used by a buddy. For example, the Aqua Lung ABS Octopus features a unique 120-degree angle between the hose and mouthpiece, which is specifically designed to facilitate comfortable air sharing, ensuring a natural head position for the recipient. Similarly, the reversible hose attachment of the SCUBAPRO R105 Octopus offers flexibility in routing, preventing kinks and ensuring the octopus is easily accessible and oriented correctly, regardless of tank setup. Overlooking these ergonomic features can complicate emergency air sharing.